Performance studies of new optics for the time-of-flight detector of the AFP project.

We present the results of performance studies of the upgraded optical part of the time-of-flight subdetector prototype for the AFP (ATLAS Forward Proton) detector obtained during the test campaign in a synchrotron test-beam facility with 5 GeV electrons at the DESY laboratory (Hamburg, Germany) in June 2019. The detection of the particle arrival time is based on generation of Cherenkov light in an L-shaped fused silica bar. In the previous version of the ToF, all bars were made of two pieces (radiator and light guide) glued together with a dedicated glue (Epotek 305). This solution suffers from additional radiation damage of glue. We adopted a new technique of bar production without the need of glue. The new bars have a higher optical throughput by a factor of 1.6, reduced fragility, and better geometrical precision.

BRDF profile of Tyvek and its implementation in the Geant4 simulation toolkit.

Diffuse and specular characteristics of the Tyvek 1025-BL material are reported with respect to their implementation in the Geant4 Monte Carlo simulation toolkit. This toolkit incorporates the UNIFIED model. Coefficients defined by the UNIFIED model were calculated from the bidirectional reflectance distribution function (BRDF) profiles measured with a scatterometer for several angles of incidence. Results were amended with profile measurements made by a profilometer.

Optical 3D methods for measurement of prosthetic wear of total hip arthroplasty: principles, verification and results.

Total hip arthroplasty (THA) significantly improves the quality of life in majority of patients with severe osteoarthritis. However, long-term outcomes of THAs are compromised by aseptic loosening and periprosthetic osteolysis which needs revision surgery. Both of these are causally linked to a prosthetic wear deliberated from the prosthetic articulating surfaces. As a result, there is a need to measure the mode and magnitude of wear. The paper evaluates three optical methods proposed for construction of a device for the non-contact prosthetic wear measurement. Of them, the scanning profilometry achieved promising combination of accuracy and repeatability. Simultaneously, it is time efficient to enable the development of a sensor for wear measurement.